How to create a whitelist on the Central device

[purgoufr]

I want to create a whitelist on the Central device. Because there is a lot of peripheral devices around and I just want to connect one peripheral device. First I register the address of the central device to the peripheral device. When I work with a single peripheral device and a single central device, I can send commands from the central device to the peripheral device. But when I have more than one peripheral device in the vicinity, I can not send commands to the peripheral device registered from the central device. So I decided to create whitelist on the central device to connect the peripheral device which I registered before. But I don't know how. Do you have any example? (except ble_app_hrs)

Function to start scanning code;

// Function to start scanning
void scan_start(void) {
  ble_gap_whitelist_t   whitelist;
  ble_gap_addr_t      * p_whitelist_addr[BLE_GAP_WHITELIST_ADDR_MAX_COUNT];
  ble_gap_irk_t       * p_whitelist_irk[BLE_GAP_WHITELIST_IRK_MAX_COUNT];
  uint32_t              err_code;
  uint32_t              count;    

  err_code = pstorage_access_status_get(&count);
  APP_ERROR_CHECK(err_code);

  if (count != 0)
  {
      m_memory_access_in_progress = true;
      return;
  }
	
  // Initialize whitelist parameters.
  whitelist.addr_count = BLE_GAP_WHITELIST_ADDR_MAX_COUNT;
  whitelist.irk_count  = 0;
  whitelist.pp_addrs   = p_whitelist_addr;
  whitelist.pp_irks    = p_whitelist_irk;

  // Request creating of whitelist.
  err_code = dm_whitelist_create(&m_dm_app_id,&whitelist);
  APP_ERROR_CHECK(err_code);
	
  if (((whitelist.addr_count == 0) && (whitelist.irk_count == 0)) ||
      (m_scan_mode != BLE_WHITELIST_SCAN)                        ||
      (m_whitelist_temporarily_disabled))
  {
      APPL_LOG("THERE IS NO WHITELIST\r\n");		//Debug Note
      // No devices in whitelist, hence non selective performed.
      m_scan_param.active       = SCAN_ACTIVE;        // Active scanning set.
      m_scan_param.selective    = SCAN_SELECTIVE;     // Selective scanning not set.
      m_scan_param.interval     = SCAN_INTERVAL;			// Scan interval.
      m_scan_param.window       = SCAN_WINDOW;  			// Scan window.
      m_scan_param.p_whitelist  = NULL;        				// No whitelist provided.
      m_scan_param.timeout      = 0x0000;       			// No timeout.
			
  }
  else
  {
      APPL_LOG("WHITELIST WAS FOUND\r\n");		//Debug Note
      // Selective scanning based on whitelist first.
      m_scan_param.active       = 1;            // Active scanning set.
      m_scan_param.selective    = 1;            // Selective scanning not set.
      m_scan_param.interval     = SCAN_INTERVAL;// Scan interval.
      m_scan_param.window       = SCAN_WINDOW;  // Scan window.
      m_scan_param.p_whitelist  = &whitelist;   // Provide whitelist.
      m_scan_param.timeout      = 0x001E;       // 30 seconds timeout.
		
      m_scan_mode = BLE_WHITELIST_SCAN;
  }

  err_code = sd_ble_gap_scan_start(&m_scan_param);
  APP_ERROR_CHECK(err_code);
}

[Petter Myhre]

So you are actually able to connect? Are you sure you are connecting to the peripheral you want to send commands to? How do you know? How does the central know which peripheral to connect to? (If all are advertising with the same UUID and this is what the central uses to filter what devices to connect to) You can use a whitelist to filter all advertisements that are not in the whitelist, but then you must put in the address of the device that you want to accept advertisements from.

The button is used to start scanning and connection? What happens the second time it is pressed? Disconnection and then start scanning and new connection?